The invention relates to a vertical hoisting system of a cab. The vertical hoisting system is composed of a cab bracket, a middle hoisting frame, a tail end hoisting frame, a fixed frame, a hydraulic oil cylinder, a fixed pulley wheel set and a movable pulley wheel set. The problems that a cab of an existing high-clearance sprayer usually adopts a fixed manner so that a driver cannot conveniently get on and off the machine, the height of the machine is too high and has requirements on height limitation of roads, and the gravity center of the machine is slightly high are solved; the machine with a hoisting function is a parallel four-connection-rod mechanism usually, the our-connection-rod mechanism has large requirements in a working space, and requirements on machining and assembling processes are high; the hoisting operation of the cab is not stable, and shaking and swaying are easy to generate; a structural design is optimized, and the man-machine matching efficiency is improved and is particularly represented that the visual field is improved by hoisting the cab in a working process, and the hoisting operation of the cab is stable; the cab is descended when the machine is driven on a road so that the gravity center of the machine is lowered and the stability in a driving process of the machine is improved.